18699993 has 24 divisors (see below), whose sum is σ = 29244488. Its totient is φ = 11446272.

The previous prime is 18699973. The next prime is 18699997. The reversal of 18699993 is 39999681.

It can be written as a sum of positive squares in 4 ways, for example, as 2442969 + 16257024 = 1563^2 + 4032^2 .

It is not a de Polignac number, because 18699993 - 2¹⁰ = 18698969 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18699997) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32121 + ... + 32697.

Almost surely, 2^18699993 is an apocalyptic number.

18699993 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18699993 is a deficient number, since it is larger than the sum of its proper divisors (10544495).

18699993 is a wasteful number, since it uses less digits than its factorization.

18699993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 873 (or 870 counting only the distinct ones).

The product of its digits is 944784, while the sum is 54.

The square root of 18699993 is about 4324.3488527176. The cubic root of 18699993 is about 265.4282526082.

The spelling of 18699993 in words is "eighteen million, six hundred ninety-nine thousand, nine hundred ninety-three".